New membranes resist biofouling using sunlight

Membranes in large-scale water-treatment processes are often fouled by accumulation of bacteria or their biofilms. Now, a team of researchers from Washington University St. Louis (WUSTL; St. Louis, Mo.; www.wustl.edu) have combined graphene oxide and bacterial nanocellulose to design a highly efficient ultrafiltration membrane that resists biofouling. “Photothermal nanomaterials like graphene oxide absorb light effectively, and the absorbed light is quickly converted into heat. Thus, the membrane gets hot, killing microorganisms on its surface and minimizing biofilm formation. This new membrane design uses the natural energy of sunlight to resist biofouling on membranes,” explains Young-Shin Jun, professor of Energy, Environmental & Chemical Engineering at WUSTL. Previously reported nanomaterial-enabled membranes often suffer from short operational lifetimes and poor physical and chemical stability that can result in nanomaterials leaching into water, adds Srikanth Singamaneni, professor of Mechanical Engineering and Materials Science at WUSTL. To secure the photothermal materials within the membrane’s structure, the team from WUSTL started with a bacterial culture medium where cellulose nanofibers grow into a matrix. Next,…